In recent years, as a power supply of portable electronic equipment such as a portable phone or a portable personal computer, a battery, in particular a secondary battery, is used. As one example of a secondary battery, a lithium ion secondary battery is known to have a relatively large energy density. In such a secondary battery, a liquid electrolyte (electrolytic solution) of an organic solvent or the like is conventionally used as a medium for allowing ions to move. However, in a secondary battery using an electrolytic solution, there is a problem such as leakage of the electrolytic solution. Therefore, development of a layered solid-state battery in which all the constituent elements are constituted of solids using a solid electrolyte is being advanced.
As a structure of such a layered solid-state battery, Japanese Patent Application Laid-open (JP-A) No. 2004-158222 (hereafter referred to as Patent Document 1), for example, discloses a structure of a multi-layered battery in which battery cells, each of which is a thin-film solid-state lithium ion secondary battery, are stacked in plural stages.
In one structure disclosed in Patent Document 1, in a layered solid-state battery in which plural pieces of power-generating elements, each of which is constructed by stacking a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a collection layer, are stacked, the layers are sequentially stacked on one substrate by utilizing a function of the collection layer (metal film) serving as an ion-conductively insulating film, without using a new insulating layer between the individual power-generating elements.
In another structure disclosed in Patent Document 1, in a layered solid-state battery in which plural pieces of power-generating elements, each of which is constructed by stacking a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a collection layer, are stacked through the intermediary of an electron-conductively and ion-conductively insulating insulation layer, withdrawal tabs disposed on outer peripheral parts of the collection layers are disposed by being drawn out to the outside of the layered body perpendicularly to the layered body direction; via holes for connection penetrating through the insulation layer are provided in these withdrawal tabs; the via holes are made capable of embedding metal electrodes therein for connection; and connections of series type, parallel-type, and series-parallel-type can be selected by a combination of these connections.
Patent Document 1: Japanese Patent Application Laid-open (JP-A) No. 2004-158222